Patent Literature 1, for example, discloses a structure in which a first electric circuit (for example, an inverter) and a second electric circuit (for example, a junction box) are disposed in one casing, and are electrically interconnected via one bus bar. In this structure, a partition member divides the inside of the casing into a first space and a second space, the first electric circuit is disposed in the first space, and the second electric circuit is disposed in the second space. The partition member is provided with an opening, and the bus bar passes through this opening.